Typical blasting systems can involve one or more blasting machines, each in direct communication with a plurality of detonators. Command signals can be transmitted to the blasting machine(s) by a central command station that is located remote from the vicinity of the blast. Such command signals may include signals to ARM, FIRE or DISARM the detonators.
The communication between the central command station and the blasting machine typically occurs via radio-communication, but may also involve direct electric or non-electric connection. Likewise, the communication between the blasting machine and the detonators may also involve radiocommunication, but more typically involves direct connection, for example, via electrical wiring. In any event, command signals transmitted by the central command station are received by the one or more blasting machines, and subsequently relayed to the detonators.
In any blasting system, safety considerations are paramount. Several systems and methods have been previously developed to help improve the safety of blasting systems, with the intention of preventing unintentional detonator actuation, premature blasting prior to proper evacuation of the blast area, or unauthorized use of the blasting system.
In one example, U.S. Pat. No. 4,674,047 issued Jun. 16, 1987, discloses a detonation system in which a number of electronic detonators can each be programmed with a unique identification number and delay time by means of a user-operable firing console. A command from the firing console includes a unit identification code which is used to address or designate a specific integrated delay detonator. The system may further include additional security code measures to help prevent unauthorized use.
In another example, U.S. Pat. No. 5,298,438 issued Mar. 22, 1994 discloses an apparatus for timing and initiating a multi-shot blast involving a transportable programming tool for individually programming a plurality of electronic detonator arrangements with delay time data relative to a common initiate command signal. The detonators are all connected to a control unit via a single cable, and an initiation signal triggers the detonator delay units to start timing our their respective programmed delay times. A similar arrangement is disclosed by U.S. Pat. No. 5,894,103 issued Apr. 13, 1999. However, the system provides for multiple detonator circuits in connection with a control unit, wherein each detonator circuit can be separately programmed with a delay time. Moreover, each detonator circuit is assigned a specific identification code for individual communication with the control unit. The system further includes a portable device for programming the delay times into the control unit.
U.S. Pat. No. 5,520,114 issued May 28, 1996, discloses an apparatus and method for firing detonators involving a programming unit for programming a series of ignition modules with delay times. The firing console can subsequently simultaneously interrogate the ignition modules, which send back the requested information to program the firing console with the delay times. The firing console and the programming unit may be fitted with encoding means designed to limit their access to authorized users, and with means for internal mutual recognition before the transfer of delay times from the programming unit to the firing console. Further optional safety features require the operator to know recognition codes to access the firing and programming consoles. For example, the firing console can be fitted with a magnetic card for authorizing its use.
In yet another example, International Patent Application PCT/AU98/00929 published Nov. 6, 1998 discloses an electromagnetic induction detonation system involving an automated radio charge (ARCH) module connectable to an electric detonator and a transducer. The system further includes a remote controller for sending instructions to the transducer module from a remote location. Actuation of the detonator requires the transducer module to generate an electromagnetic field which is used to power the ARCH module and provide a detonation current. In one embodiment, the remote controller includes means for the manual entry of instructions by which a user must enter a valid identification number within a predetermined time period in order for the remote controller to establish a radio communication link with the transducer unit. In another embodiment, the remote controller unit includes a processor means for generating a unique identification code word which is continuously transmitted until an acknowledgement signal is received from the transducer unit corresponding to the identification code word. In the absence of receipt of the acknowledgement signal within a predetermined time period the remote controller adopts a ‘reset’ mode, thereby requiring a user to enter a new valid identification code before communication with the transducer unit is re-established.
In another example, International Patent Application PCT/EP99/08122 published May 11, 2000 discloses a detonation system for detonators which can be initiated by radio signals. The system includes at least one initiation device connected to at least one detonator, and a detonation device that can communicate with the initiation device via radio signals. At least one of the initiation units contains a removable data carrier which can be inserted into the detonation unit. In addition, the detonation device includes a reading device for reading the data on the inserted data carrier. The initiation device and the data support allocated thereto contain identical identification characteristics and information necessary for initiating the connected detonator. The initiation device is activated by removing the data carrier, and can be placed in a receiving state (or a transmitting/receiving state for bi-directional communication). Likewise, the detonation device is placed in a transmitting standby mode or a transmitting and receiving standby mode after inputting the data from the data carrier.
In a final example, International Patent Application PCT/AU00/00351 published Oct. 26, 2000 discloses a method and system for controlling a blasting network for use where spurious command signals may be passed through a blasting controller to the blasting network without the authorization of the authorized user, for example when the controller is connected to the Internet or Intranet. The system includes a firewall whereby the communication link between the controller and the blasting network can be placed in a control mode by a switch. In the control mode, designated unsafe messages are prevented from reaching the blasting network.
The detonation systems of the prior art thus provide various means for improving the safety and security of the blasting process. Nonetheless, no blasting system can provide absolute safety and security, and there remains a need for improved blasting systems configured to reduce the possibility of inappropriate detonator actuation or unauthorized use.